The force of the explosion caused raised part of the highway to collapse.

Italian firefighters tweeted that they had sent rescue and emergency squads, including one from their urban search and rescue team.

A dashcam captured the Bologna highway explosionSource:Supplied

The explosion has injured dozens of people.Source:Supplied

A firefighter walks at the site where a tanker truck exploded on a motorway just outside Bologna, northern Italy. Picture: AFPSource:AFP

Black smoke fills the air from the crash scene.Source:AFP

Images released earlier by the fire service showed burning cars in an adjacent carpark.

One video filmed by a motorist circulating on Twitter shows the moment the tanker exploded, when a black plume of smoke is suddenly swept away by a powerful ball of flame that takes over the entire horizon.

A video published on Twitter by the fire service showed a huge column of black smoke billowing from the wreckage of the truck.

Images released earlier by the fire service showed burning cars in an adjacent carpark.

Smoke billows at the site where the tanker truck exploded.Source:AFP

Injured people receive medical attention at a nearby hospital.Source:AFP